Updating the Add-On Version
This is sometimes required as the add-on window holds on to cached JavaScript code files for a long time, and does not seem to check if these files are out of date on a regular basis.
To clear cached files & get all files of the current version of any add-ons store Office add-on, follow these steps:
Open the add-on you want to update
Click anywhere within it’s window
Click `Ctrl + Shift + R` to hard reload the files of the add-on, forcing fresh code retrieval
As a note, certain file types do not get cached, meaning you can run into situations in which different files are from different versions of the add-on.
HTML files in particular do not get cached, which can lead to situations in which the page shows the user an up to date version number, but the code behind the page is actually from a different older version.